Abstract
High-pressure mafic granulites containing granoblastic garnet, quartz, and minor hornblende have been found from the Song Ma Suture zone in northern Vietnam, regarded as a microcontinental boundary between the South China and Indochina blocks. Fine-grained symplectite formed during the decompression stage is developed in the granulite and is divided into orthopyroxene + plagioclase and orthopyroxene + clinopyroxene + plagioclase ± hornblende. The former replaces garnet and the latter is regarded as a breakdown of sodic clinopyroxene. Detailed observation and careful data selection revealed that the high-Mg and low-Ca garnet should be in equilibrium with the precursor sodic clinopyroxene, and the pair indicates high-temperature and -pressure conditions (910-930 °C at 1.9-2.0 GPa). Although we could not obtain quantitative age data from the high-pressure granulite, the U-Th-Pb age (233 ± 5 Ma) of pelitic gneiss strongly suggests a Middle to Early Triassic metamorphic event. If the age indicates the timing of the high-pressure granulite-facies metamorphism, it might be related to a continental collision setting by following crustal subduction. According to the metamorphic signatures, north to central Vietnam may be regarded as an orogenic belt formed by the micro-continental collision between the South China and Indochina cratons.
| Original language | English |
|---|---|
| Pages (from-to) | 127-138 |
| Number of pages | 12 |
| Journal | Comptes Rendus - Geoscience |
| Volume | 340 |
| Issue number | 2-3 |
| DOIs | |
| Publication status | Published - Feb 1 2008 |
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All Science Journal Classification (ASJC) codes
- Global and Planetary Change
- Earth and Planetary Sciences(all)
Cite this
Discovery of high-pressure granulite-facies metamorphism in northern Vietnam : Constraints on the Permo-Triassic Indochinese continental collision tectonics. / Nakano, Nobuhiko; Osanai, Yasuhito; Minh, Nguyen Thi; Miyamoto, Tomoharu; Hayasaka, Yasutaka; Owada, Masaaki.
In: Comptes Rendus - Geoscience, Vol. 340, No. 2-3, 01.02.2008, p. 127-138.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Discovery of high-pressure granulite-facies metamorphism in northern Vietnam
T2 - Constraints on the Permo-Triassic Indochinese continental collision tectonics
AU - Nakano, Nobuhiko
AU - Osanai, Yasuhito
AU - Minh, Nguyen Thi
AU - Miyamoto, Tomoharu
AU - Hayasaka, Yasutaka
AU - Owada, Masaaki
PY - 2008/2/1
Y1 - 2008/2/1
N2 - High-pressure mafic granulites containing granoblastic garnet, quartz, and minor hornblende have been found from the Song Ma Suture zone in northern Vietnam, regarded as a microcontinental boundary between the South China and Indochina blocks. Fine-grained symplectite formed during the decompression stage is developed in the granulite and is divided into orthopyroxene + plagioclase and orthopyroxene + clinopyroxene + plagioclase ± hornblende. The former replaces garnet and the latter is regarded as a breakdown of sodic clinopyroxene. Detailed observation and careful data selection revealed that the high-Mg and low-Ca garnet should be in equilibrium with the precursor sodic clinopyroxene, and the pair indicates high-temperature and -pressure conditions (910-930 °C at 1.9-2.0 GPa). Although we could not obtain quantitative age data from the high-pressure granulite, the U-Th-Pb age (233 ± 5 Ma) of pelitic gneiss strongly suggests a Middle to Early Triassic metamorphic event. If the age indicates the timing of the high-pressure granulite-facies metamorphism, it might be related to a continental collision setting by following crustal subduction. According to the metamorphic signatures, north to central Vietnam may be regarded as an orogenic belt formed by the micro-continental collision between the South China and Indochina cratons.
AB - High-pressure mafic granulites containing granoblastic garnet, quartz, and minor hornblende have been found from the Song Ma Suture zone in northern Vietnam, regarded as a microcontinental boundary between the South China and Indochina blocks. Fine-grained symplectite formed during the decompression stage is developed in the granulite and is divided into orthopyroxene + plagioclase and orthopyroxene + clinopyroxene + plagioclase ± hornblende. The former replaces garnet and the latter is regarded as a breakdown of sodic clinopyroxene. Detailed observation and careful data selection revealed that the high-Mg and low-Ca garnet should be in equilibrium with the precursor sodic clinopyroxene, and the pair indicates high-temperature and -pressure conditions (910-930 °C at 1.9-2.0 GPa). Although we could not obtain quantitative age data from the high-pressure granulite, the U-Th-Pb age (233 ± 5 Ma) of pelitic gneiss strongly suggests a Middle to Early Triassic metamorphic event. If the age indicates the timing of the high-pressure granulite-facies metamorphism, it might be related to a continental collision setting by following crustal subduction. According to the metamorphic signatures, north to central Vietnam may be regarded as an orogenic belt formed by the micro-continental collision between the South China and Indochina cratons.
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U2 - 10.1016/j.crte.2007.10.013
DO - 10.1016/j.crte.2007.10.013
M3 - Article
AN - SCOPUS:39149118916
VL - 340
SP - 127
EP - 138
JO - Comptes Rendus - Geoscience
JF - Comptes Rendus - Geoscience
SN - 1631-0713
IS - 2-3
ER -